Device for the photographic registration of vibrations in line form.



A. POLLAK. DEVICE FOR THE PHOTOGRAPHIG REGISTRATION OF VIBRATIONS INLINE FORM. APPLICATION FILED JAILZQ, 1913.

1,092,594. Patented Apr. 7, 1914;

INVENTOR WITNESSES: 7 [3) Atzomzcgas,

UNITED STATES PATT ANTON POLLAK, 0F PARIS, FRANCE.

DEVICE FOR THE PHOTOGRAPHIC REGISTRATION 'OF VIBRATIONS IN LINE FORM. I

Specification of Letters I'atent.

Patented Apr. t, 114.

Application filed January 28, v191.3. Serial No. 744,851.

To. all whom it may concern: Be it known that I, AN'noN POLLAK, asubject of the King of Hungary, residing in aris, France, have inventedcertain new and useful Improvements in Devices for the PhotographicRegistration of Vibrations in Line Form, of which the following is aspecification.

The invention starts from the system of photographic registrations ofvibrations in line form which has become known through the Pollak-Viragrapid telegraph, in which the vibrations are transmitted through one orthrough two telephones traversed by suitable current combination to amirror in such a manner that the rays from a point of light fall uponthe mirror and are reflected therefrom and received upon alight-sensitive paper strip in such a way for example that certain linesshow a directly readable script. The invention renders it possible toattain in exactly horizontal and somewhat drawnout linear form aregistration far exceeding in sharpness that which has been previouslypossible. Moreover the device in accordance with the invention makes itpossible to directly and clearly observe the entire operation so thatany disturbances can be immediately recognized and corrected.

In the accompanying drawing the subject matter of the invention isillustrated in one embodiment in diagrammatic perspective view.

The mirror, 1, which rests freely rotatable upon the stationary point,2, is in the well known manner moved by leaf springs, 3, and 4, each ofwhich by means of a small rod is directly under the control of atelephone member. From the one telephone there arise horizontalmovements and from the other vertical movements, and as a matter of factthe mirror rotates under the action of the spring, 3, about a horizontalaxis and under the action of the spring, 4, about a vertical axis by thecompounding of horizontal and vertical components we can, as is wellder, 13, for example, of

metal, which is provided with a small slit- 14.

The small portion of the filament shining outward through the slit canby means of the objective, 11, be represented as a point of light whichafter reflection by the mirror, 1, registers upon the sensitive paper,6, t e movements of the mirror. In order to be able to receive theregistration in linear form upon a wide strip of paper there must beglven to the point of light upon the paper, 6, at the point ofillumination, 9, a movement corresponding to that given to the lines bythe paper. That is to say, the point of light must not only movetransversely across the paper but must have also a slight longitudinalmovement correspondingto the movement of the paper. For this purpose inthe well known manner in the metal cylinder, 13, there is fastened thesmall slit, 14, in the form of a screw-thread and the metal cylinder,ranged. If now the metal cylinder is rotated then a portion of thefilament, 12, progressing from one end to the other will con-- stantlyilluminate the mirror, and the registered point of light is displacedand writes a line which as soon as the end of the screw-shape slit comesbetween the filament 12 and mirror, 1, is interrupted whereupon onfurther rotating the commencement point of the same located at the otherend of the screw-thread, .14, allows the light of the filament, 12, tofall upon the mirror whereupon the point of light begins a new line. Thelength of a line is accordingly determined by the difference whichresults from those successive registering points'of the incandescentfilament which corresponds to the two end points of the screw-shapeslit.

The portrayed point of light shows as a rectangle the-height of which isdetermined by the thickness of the illuminating filament, while thewidth results from the width of the screw-shape slit, 14. Now theilluminating filament, 12, is necessarily farther re moved from theobjective, 11, than the position of the slit in the cylinder, 14, andthis lies between the filament and the objective. It follows therefromthat the one limitation of the light point, in the direction of thethickness of the filamentfalls away farther from the objective than theother limitation, in the direction of the width of the slit, so that thetwo limitations lie in different planes and consequently also thecorrespond ing representations of the picture portions light oint inthis case stand forth still more plain y. An approximate correction ofthis diificulty consists in striving to bring the illuminating filamentinclosed in the 1ncandescent lamp as near as ossible to the glass of thelamp in the direction of the mirror in order to make as small aspossible the difference between the two distances. A perfectly sharppoint of light cannot be attained in this way, and there arises also afurther disadvantage that the inner wall of the lamp in the icinity ofthe glowin filament becomes exceedingly blackened andin fact inconsequence of the excessive nearness of the filament gets black sorapidly that the lamp must be exchanged after a very short burningperiod. This disadvantage is materially remedied by the presentinvention by arranging in the vicinity of the screw-shape slit, 14,between the source of light and the objective a cylindrical lens, 16,which causes the light rays to be refracted only in the direction of thewidth of the slot while in the direction of the thickness of thefilament they experience no change. This cylindrical lens allows ofbringing into the same lane, and thereby attaining a sharp point 0 lightupon the paper, 6, the points which are to be registered arising fromvarious lanes and which, as mentioned, would fall in difi'erent copyingplanes if there were no rectification.

This rectification can at will be effected by means of concave or convexcylindrical I lenses; it is, however, advantageous to employ convexlenses for a purpose hereinafter explained.

It is in fact desirable to obtain the registration in the longestpossible lines. The length of the lines depends principally upon thepitch of the screw-shape slit 14. This pitch is however limited sincethe diameter of the rotating cylinder, 13, is limited'and the slitunder. increasing pitch soon becomes oblique to such an extent that thesharpness of the point of light suffers therefrom.

An enlargement of the lines (without increasing the sharpness) isattainable in accordance with the invention by arranging between theslit, 14, and the objective, 11, a

convex lens which causes an enlarged image of the line to appear on thepaper, 6. Since however this enlargement is only desired in thedirection of the movement of the point of light, that is, in thedirection of the lines, instead of a'convex spherical lens there isemployed a convex cylindrical lens. Thereby one may employ a single lensfor both the purposes mentioned, namely for the enlarging of the linesand also for the rectification of the point of light. There followsautomatically an enlargement of the length of lines if for rectificationof the light point a convex and not a concavecylindrical lens is chosen..One would however (if one only had in view the rectification of thepoint of light) in general be inclined to strive to accomplish theobject with the thinnest possible cylinderlenses, since these absorbless light and one would consequently choose cylindrical lenses with thegreatest possible focus, whereby there would be produced only aninconside'rable' increase in the length of the lines. Therefore 'inthe-matter of the present invention there is chosena convex cylindricallens with the shortest possible focus (and which of course is thickerfor that rea son) and the distance of the objective is correspondinglychanged; whereby without the addition of other convex objectives asufficient enlargement of the copied distance of the end point of thepitch of the screw slit is obtained and consequently an increased linelength is obtained upon the paper.

The device in accordance with the invention makes possible moreover theconstant observation of the photographic copying without interruptingthe same. In former devices of this kind this observation would takeplace only very imperfectly, sincethe observer cannot observe directlythe point of light which acts upon the side of the lightsensitive paper,6, which is turned away from him, but only can observe it feebly shiningthrough the paper while, on removing the paper. 6, the vibrations of thepoint of light can be easily followed by the eye upon a matte diskattached to the illuminated point, 9. In order now to make it possiblethat the characters even during the photographic printing can beobserved, the screw-shape slit, 14, is lengthened considerably more thanone pitch, and thereby at each revolution at predetermined timeintervals (or incase the lengthening amounts to one whole pitch,constantly) a second tions of the rotating cylinder, 13, the filament,12, can shine through two slit portions onto the mirror and in this waythe movement of the mirror, 1, is repeated at the same time by twopoints of light, the second one of which forms the continuation of theline out over the paper. The matte disk is in this case arranged closeto*the paper strips and forms the window, 17, which is nevercovered bythe paper, 6, and upon which the second light copy reaching out over thepaper becomes visible and allows the operation to be followed withoutthe printing being interrupted so that any disturbance can beimmediately recognized and corrected.

The metal cylinder, 13, with'the incandesslit for pr ucin cent lamp, 10,is arranged parallel to the oblique direction of the paper strip,6,whichis uniformly pushed forward in the direction ofthe arrow, 15, sothat upon the paper the lines stand forth at uniform distances in thetransverse direction; in consequence of the pushing forward of the-paperstrips the'lines however assume an oblique situation. This disadvantageis corrected in accordance with the invention by arranging the filament,12, of the lam 10, somewhat inclined in respect to the direction of theforward movement, 15, of the paper strip.

As a matter of 'fact the lines hereby appear on the window, 17 in aninclined position, which however, since there is only a question ofobservation at this point, is not disadvantageous. The relativelyinclined position of the incandescent filament can be attained in anydesired manner for example by placin the whole lamp, 10, obliquely inthe'cylin er, 13, in case the filament, 12, is parallel to the tubularaxis of the incandescent lamp, or only the filament itself may bestretched obliquely in the interior of the incandescent lamp, in whichcase the lamp itself must be placed per endicular to the direction, 15,or only slig tly inclined. Also the rotating cylinder, 13, can bearranged obliquely in order to assist the inclined position of thefilament 12. I claim as my invention 1. Device for the photographicprinting of vibrations in line form by means of a point of light and forthe simultaneous ob-' servation of the printing, said, device includingin combination a movable mirror for reflecting a point of light upon asensitized paper strip, av linear source of light, an

opaque rotating cylinder inclosing said source of li ht and providedwith a iral a convex cylin rical lens between said source of light andsaid mirror whose focal length is such in proportion to the distance ofthe mirror that sald lens serves to bring into a common plane theboundaries of the a moving point of llght,

point of light lying in different planes and serves also to increase thelength of the line.

2. Device for the photographic printing of vibrations in line form bymeans of a point of light and for the simultaneous observation of theprinting, said device includin in combination a movable mirror for reecting a point of light upon a sensitized paper strip, a linear sourceoflight, an opaque rotatin cylinder inclosing said source of light anfiprovided with a s iral slit for producing a moving point of light, acylindrical lens arranged in the course of light between the mirror andthe cylinder and adapted to bring into a common plane the boundaries ofthe pointof light lying in diiferent planes, said cylinder having asupplementary spiral-slit portion, a. matte screen located outside ofthe paper strip and cooperating with said supplementary spiral slit soas to permit the ap earance of a second vibrating point of light for thepurpose of observing the rinting.

3. Device for the photographic printing of vibrations in line form bymeans of a point of light and for the simultaneous observation of theprinting, said device including in combination a movable mirror tizedpaper strip, a linear source of light, an opaque rotating cylinderinclosing said source of light and provided with a spiral slit forproducing a moving point of light, said source of ight being arrangedobliquely to the direction of forward movement of the paper strip, inorder, in spite of the forward movement of the paper, to obtain linesrunning perpendicular to the borders of the strip. Y

In witness whereof, I have hereunto signed my name in the presence oftwo subscribing witnesses.

JOHN BAKER.

for reflecting a point of light upon a sensi-.

